Firearm



12x R. J. T'IURNER FIREARM I V Filed Jan. 5, 1942 2 Sheets-Sheet 1 Decflz, 1944 Y R J. TURNER 2,365,142

FIREARM v I Filed Jan. 3. 1942 2 Sheets-Sheet 2 IPUSSB/ l d. TU E/VE INVENTOR.

Patented Dec. l2, 19

AEN

2,365,142 FIREARM; yaussen .1. Turner, Butler, ra.

Application January 3, 1942,. Serial No. 425,541

1o claims. (c1. 4M)

This invention relates generally-to rearms and more particularly to breech loading gas-operated automatic rearms.

This invention may be conveniently applied' to all types of full and semi-automatic firearms such as machine guns, heavy rines, lightV carbines, automatic pistols and other similar self or automatic loading weapons.

The principal object of this invention is the provision of an accurate and rugged automatic rearm the structure of which is reduced to a very few number of parts making the firearm simple in construction and in operation and economical to manufacture.

Another object is the provision of an automatic rearm that may be completely dismantied without the use of hand tools.

Another object is the provision of a breech loading gas-operated automatic firearm that employs the gas pressure of the charge to unlock, withdraw and open the breech; cock the piece, extract and eject the shells, insert a fresh load from the magazine, lock the breech and re.the load.

Another object is the provision of a double stepped trigger that converts the full automatic iirearm into semi-automatic firearm which requires the trigger to be pulled to :re each shot.

Another object is the provision'of an improved gas cylinder and gas cylinder barrel connection that may be quickly detached for cleaning and which provides an improved gas sealed joint that will not freeze due to carbonization or other causes.

Another object is the provision of a straight gas vent in the barrel of the firearm that can be readily cleaned when the gas cylinder is removed.

Another object is the vprovision of a gas vent disposed to intersect the bore of the barrel at a trailing angle relative to the ight of the projectile.

Another object is the provision of an operat-` ing arm having a cam surface which locks the breech-block in its nring position and when initially retracted' by gas pressure unlocks the breech-block bywithdrawing the cam surface i from its operating position.

Another object is the provision of a novel link which connects the operating arm with the breech-block and serves to dislodge the breechblock from its seat and slide it rearwardly to open-the breech, cock the piece, and extract and eject the empty shell.

Another object is the provision of a novel ring pin and an extension on the breech-block connecting link which prevents the ring pin from engaging the primer unless the breechblock is fully locked in its closed position.

Another object is the provision of a shoulder in the side of the receiver against which the breech-block may be seated and locked in its closed position.

Another object is the provision of a receiver which is tightly closed when the breech-block is locked in the ring position and is opened instantaneously when the empty shell is ejected through an opening in the operating arm when in its retracted position.

Other objects and advantages appear in the following description and claims.

In the accompanying drawings a light semiautomatic carbine is employed as a practical embodiment to illustratethe principles of this Fig. 5 is a top plan view of the ring pin in the i'lring position with the link illustrated in dotted lines.

Fig. 6 is a view similar to Fig. 5 illustrating the firing pin locked in its retracted position.

Fig. 7 is a perspective view of the under side of the link.

Fig. 8 is a side elevation of the hammer and trigger mechanism with parts broken away. illustrating the semi-automatic feature.

Referring to the drawings the body of the rearm comprises three parts, the barrel I0, the receiver or frame II and the grip or stock I2. Thebreech end I3 of the barrel is iitted to the front end of the receiver II and projects into the forward end of the receiver chamber I4. The stock I2 is secured to the rear end of the receiver or frame Il. The forward end of the receiver chamber I4 is open at the bottom to admit the cartridge magazine I5. 'The side of the receiver is provided with opposed grooves I6 which extend for the full length thereof and which slidably carry the actuating or operating arm I1. On the "same side the rear portion of he receiver chamber I4 is closed vby a removable :over plate I8 which retains the operating arm i1 and covers the hammer 20 and the trigger nechanism 2l. By rst removing this cover )late the whole fire-arm may be dismantled.

The breech-block 22 is arranged to slide longitudinally within the receiver chamber I4 and :arries the firing pin 23. The front end of the Jreech-block is recessed in the usual manner as ndicated at 24 to receive the rim and primer 3f the cartridge shell 25. The extractor claw Z6 is pivoted in the side of the breech-block and extends forwardly and inwardly to catch on the rim of the cartridge to extract it from the breech of the barrel. An ejector 21 is xed to the wall cf the chamber I4 and is arranged to strke the rim of the cartridge shell and swing it toward theextractx` claw when the breech-block is substantially fully retracted. An aperture 28 is provided in the forward portion of the operating arm I1 to permit the shell to be thrown out of the receiver chamber when the operating arm is in its retracted position.

In the left side at the front of the receiver chamber I4 a pocket 30 is provided which tapers towards the breech from the beveled shoulder 3|. The corresponding side of the back of the breechblock is provided with the beveled surface 32 which is complementary to and is received by the shoulder 3l. When the breech-block is brought forward until the front end engages the end of the barrel it is then shoved sideways to seat the surface 32 on the shoulder 3l. The front end of the breech-block is at this time normal to the axis of the barrel and held tightly thereagainst.

The breech-block is shoved sideways into the pocket` by means of the complementary cam surfaces 33 and 34 at the rear ends of the operating arm I1 and the breech block 22 respectively. The operating arm is permitted more travel forward than the breech block. When these two members are retracted to the rear of the receiver chamber I4 the cam surfaces 33 and 34 intermesh as illustrated in Fig. 1 and the forward travel of the operating arm moves the breech block forwardly through these cam surfaces until the front end of the breech-block engages the end of the barrel. The breech-block is stopped but the operating arm continues to move forwardly and the cam surface 33 rides up the cam surface 34 and shoves the rear end of the breech block to the left into the pocket 30. The breech block is of such length that the beveled surface 32 seats firmly onthe shoulder 3| and is locked in place by the cam surface 33 resting on the outermost surface of the cam 34.

The complementary surfaces 3I and 32 are beveled to such a degree that the blowback of the recoil would unseat and force the breechblock to the back of the receiver chamber I4 if it were not for the fact that the cam 33 lock the breech-block in its seated position.

The operating arm and the breech-block are operatively connected by. the link 35 which is provided with a depending stub shaft at each end thereof. The stub shaft 36 is journaled in a vertical opening in the rear end of the operating arm and the stub shaft 31 is journaled in the vertical opening 39 4which extends into the firing pin chamberof the breech-block. The curved portion of the cam surfaces 33 and 34 are struck from the axis of the stub shaft 31 which eliminates any interference betweenthe action of the cam surfaces and the action of the link. There is no play or clearance permitted between the link and its associated parts. IThus the operation of the cam surfaces and the link are in phase which produces a smooth and uniform action.

A portion of the outer end of the stub shaft 31 is cut away, leaving the vertical cam face 38 which lies in a plane passing through the axes of the stub shafts 36 and 31. The end. of the shaft 31 carrying the face 38 extends within the ring pin bore and is received in the slot 40 cut in the upper surface of the firing pin 23. In the structure illustrated the firing pin is prevented from rotating because the end of the stub shaft 31 contacts or lies closely adjacent the bottom of the slot 40.

When the breech-block is seated and locked in the firing position the longitudinal axis of the link 35 and the cam face 38 is disposed parallel to the transverse shoulder 4I in the firing in forming the back of the slot 40. In this position the shoulder 4I is spaced approximately five lhundredths of an inch from the face 38 as illustrated in Fig. 5. This clearance provides ample movement ,for the ring pin t0 discharge the primer of the cartridge for such movement may be five hundredths of an inch or less. If the link 35 is swung through a few degrees the cam face 38 engages the shoulder.4| to retract the firing pin 23 and prevent any forward movement thereof Thus accidental striking of the firing pin by the hammer 20, or any other unforseen object, prevents the firing pin from engaging the primer unless the breech-blcck is fully locked in its firing position with the link 35 positioned at right angles to the axis of the gun. It will be noted from the enlarged view of Fig. 5 that it takes very little swinging movement of the link 35 before the cam face 38 on the shaft 31 engages the shoulder 4I vof the firing pin. This iir ing pin safety thus becomes effective before the breech-block is unlocked from its firing position.

The rearm used for the purpose of illustrating this invention is of the semi-automatic type wherein the trigger mechanism is provided with an upwardly extending fork member 43 having opposed shoulders 44 and,45 on the inner edges of the fork members. When the -piece is being cocked by the breech-block sliding rearwardly the hammer tongue 46, which is provided with the shoulders 41 and 48 complementary to the shoul-` ders 44 and 45, is inserted between the forked members of the trigger, permitting the shoulder 41 on the tongue to engage under the shoulder 44 of the trigger before the latter has been released after the first ring. As the trigger is released the shoulder 44 slides off the shoulder 41 and the shoulder 45 engages the shoulder 48 onthe hammer tongue. When the trigger is pulled the shoulder 45 slides off the shoulder 48xand releases the hammer so that it is free to strikev the firing pin 2.3. Before the trigger canbe released the shell is fired and ejected and the ham-- mer is recocked with the shoulder 41 again `en'- gaging on the shoulder 44. If the hammer shoul,v 1 der 41 did not engage the trigger shoulder 44 while the trigger was still held back the` re-v arm would continue to shoot automatically. f i,

Suitable safety means 50 are provided to lock the trigger mechanism 2 I f The fore end of the operating arm I1 `is provided with a knob 5I which may be grasped by the hand to retract the operating arm. Upon releasing the knob the operating arm springs forward and the front of the breech-block picks up a shell from the magazine I5 and inserts it into `which is arranged to operate within the gas cylinder 54. The rod 52 and the operating arm Il are normally retained in the forward position by the actuator spring 55 which is inserted under initial compression between the piston head 53 and the actuator bracket 56. The latter 'is block 22 is pulled all the way back by the knob 5l on the operating arm Il, which action cocks the piece. 'I'he knob is then released and the actuator spring 55 moves the breech-block forsecured to the barrel and is provided with a slot for receiving the actuator rod 52.

The fore end of the Vgas cylinder 54 is provided with the/*enlarged head 5l, the peripheral'surface of which is spherically ground to fit the spherically ground socket 58 in the gas cylinder block or support 60 that is secured tothe side of the barrel adjacent the outer end.

The rear of the gas cylinder support is provided with a pair of outwardly projecting heavy fingers 5| spaced apart to receive the gas cylinder. The inner edges of the fingers which face the socket 58 are arcuately ground as indicated at 62 to receive the'arcuately ground surface of thev oppositely projecting lugs 63 on the gas cylinder 54. Thearcuate surfaces on the lingers 6| and the lugs 63 are approximately cylindrical with the center coinciding with the center of the spherical surfaces of the head 51 and the socket 58. However, the arcuate surfaces are preferably lapped in to produce increased pressure between the en- A gaging spherical surfaces as the lugs on the gas cylinder are inserted to their full depth to position the gas cylinder parallel with the barrel.

The "gas cylinder has a straight bore and the edge of the bore at the forward end is sharp and cuts away any rust or carbon formation from the surfaces adjacent the spherical seating surfaces'of the ball and socket joint when the gas cylinder is removed or replaced on the firearm. This is a very important feature of this in.- vention.

From actual practice it has been found that.

the spherical seat stays clean and shiny and providesan excellent gas seal. A gas vent 65 is drilled from the base of the spherical surface 58 through the gas cylinder support 60 and theside of the barrel into the bore thereof. This vent is straight and directs the gas to approxi mately the center of the gas cylinder. Being straight the vent maybe easily cleaned. Again thevent is angularly disposed relative to the. bore of the barrel instead of normal or radial as in the case of other gas-operated firearms. The

vent is angularly disposed in the direction of the movement of the projectile. This is important because it reduces the amount of dirt and residue of the charge that will enter and tend to clog thevent. These foreign particles have mass and when they are set in motion down the barrel behind the shot their mass resists any change in direction, especially that of complete reversal and a full magazine has been inserted, the breechward, picking up a round from the magazine and inserting into the breech. Continued movement of-the operating arm then locks the breech-block in place. When the cartridge is fired the bullet travels down the barrel Ill and after it passes the gas 'vent 64 a portion of the propellant gas blows back through the vent, filling the gas cylinder space and `driving the piston 53, the operating arm and the breech-'blockl back to the end of their stroke. I'he initial movement of the operating arm causes thetwo'opposing cam surfaces 33 and 3B on the arm and breech'block to slide relative to one another to unlock the breech block. When the operating arm Il starts to the rear the link 35 is swung clockwise, causing the face 38 on` the shaft 3lof the link to engage theshoulder 4| in .the end of the slot 40 inthe firing pin 23.

.y The swinging of the link draws the ring pin back from` the end of the breech-block and locks the same against forward movement. Any accidental breakage of the trigger mechanism causing the hammer to fall at the wrong time could not re the gun. On this stroke the empty shell is carried back by the extractor claw 26 until the rim of the shell hits the ejector 21 which throws the shell through the operating arm aperture 28 and out of the gun. As the breech-block draws away from the breech the extractor claw withdraws the empty shell and carries it back until the rim strikes the ejector, pivoting the shell on the extractor claw and swinging it out through the aperture 28 in the operating `arm, which at this instance is substantially fully retracted. During the rearward stroke "the breech block forces the hammer down, causing the shoulder 41 to engage under the shoulder 44 before the operator has a chanceto release the trigger. The breech-block then strikes the rear wall of the receiver chamber. The actuator spring is then fully compressed and the stored energy then moves the mechanism forward. Upon its forward movement the breech-block picks up another round from the magazine and inserts it into the breech. When the 'breech-block is stopped in its forward travel by the barrel l0 the continued pull of the actuator spring 55 on the operating arm causes the link to rotate counterclockwise and the two cam surfaces 33 and `34 slide upon one another, thus driving the end of the breechblock sideways into the pocket 30 and locking it When the operating arm l1 is inthe forward position the aperture 28, through which the dis- -matter that would ordinarily fall into the mechanism. The time that the aperture 28 is open during discharge is very short and the shell is on its way out during most of this time. Thus the firearm is very well protected and will continue to re after being completely buried in mud. 'Ihe cover plate I8 over the rear end of the receiver andback of which the operating arm Il slides provides quick access to the hammer and trigger mechanism.

Most gas cylinders on this type of firearm often freeze in place and have no means of easily cleaning the dirt and carbon residue or inspecting the vent. On this firearm the gas cylinder can be quickly removed when thegas piston and through the vent 64 into the gas cylinder i4 is sufficiently high to actuate the piston 53 for the full stroke of the operating arm yet this pres.- sure is effective on the piston foronly approximately the rst eighth inch of its movement.

This has been demonstrated by drilling a series of holes through the gas cylinder wall toward the ball and socket joint until the gas escapes and the piston` ceases tofunction correctly. Thus the substantially instantaneousl application actuator rod are detached from the operating into the socket andswung into place, and means of the high gas pressure on the piston is sufiiy cient to overcome the inertia and friction of the moving parts in retracting the breech-block, extracting and ejecting the empty shell and compressing the actuator spring 55. In fact, with a. vent of small cross sectional area, the pressure inder 54 is effective for only a short distance of the initial part of the piston stroke, and the force transmitted to the piston during this time f is more than that required, the remaining portion of the stroke of the piston is due to the inertia of the moving parts as the gas pressure ceases to Work on 'the piston. By extending the gas cylinder 54 kbeyond the limit of the working period of the piston stroke a suction is developed by the movement of the piston in the latter part of its stroke. This suction or sub-atmospheric pressure is substantial, since it is formed at the time the gas is flowing back through the vent 64 toward the barrel, the movement of which impedes the inrush of air through the vent into the cylinder.

The suction created in the cylinder is greatest toward the end of the piston stroke which is the time when it is most needed and effective in retarding the movement of the parts. The force4 transmitted to the piston by the gas pressure is partially snubbed, thereby reducing the force of impact between the back of the breech-block and the receiver. This suction smooths out the action and saves wear and tear of the parts.

Again the suction aids the action of the operating spring in returning the lbreech-block to the firing position.

It has been found .that if air` is admitted to the gas cylinder 54-immediately after the gas pressure has imparted the impulse to the piston, the moving parts are pounded very hard and the forces are liable to cause the. parts to break. These difculties are overcome by extending the gas cylinder to produce a suction or partial vacuum and thereby provide a snubbing action.

I claim:

1. A gas operated firearm comprising a barrel, a cylinder block secured to the barrel, a socket in the form of an arcuate sealing surface on said block, a vent connecting the socket to the bore of the barrel, a projection on the block to the rear of said socket, a gas cylinder having a seal-` ing surface complementary to the arcuate sealing surface of the socket arranged to be inserted on said cylinder arranged to engagel said projection to seat said sealing surfaces and retain the cylinder in place.

2. A gas operated firearm comprising a barrel, a cylinder block secured to the barrel, a socket in said block having an arcuate sealing surface, a vent connecting the socket to the bore of the barrel, agas cylinder having an arcuate sealing surface complementary to said sealing surface arranged to be inserted into the socket and swung into place, a pair of projections secured to the barrel and spaced apart to receive the gas cylinder therebetween, cam surfaces on the socket side of said projections, and oppositely extending lugs on said cylinder having cam surfaces arranged to engage the cam' surfaces on said projections to exert pressure on the sealing surfaces and retain the cylinder in place.

3. A gas-actuated firearml comprising a barrela socket formed with an arcuate surface and carried bythe barrel of the firearm, a vent connecting the interior of the socket with the bore of the barrel, a cylinder and piston mechanism,

the piston of which is arranged to be operatively connected with the breech mechanism of the firearm and the cylinder of which is open to its full diameter at its front end and which diameter is greater than that of the vent, a perimetrally disposed arcuate surface formed on the front of the cylinder arranged to engage and swing in thesocket, the bore of the cylinder registering with the vent when the piston is operatively connected.

4. The structure'of claim 3, characterized by the provision of means for urging the arcuate surface of the cylinderinto sealing relation with the arcuatesurface of the socket when the piston is operatively connected.

5. The structure of claim 3, characterized by the provision of' complementary surfaces carried by the barrel and the cylinder which urge the arcuate surface of the cylinder into sealing engagement with the arcuate surface of the socket as the piston is swung into operative position.

6. The structure of claim 3, characterized by the provision of a pair of fingers carrie by the barrel and a pair of radial lugs mounted on the cylinder, the fingers disposedto straddle the cylinder as the cylinder is swung into piston-operating position, and engage the lugs to urge the arcuate surface of the cylinder into sealing relation with the arcuate surface of the socket.

4'7. In a gas-operated firearm, al barrel, an arcuate socket carried by the barrel of the firearm and arranged to receive the mating end of a gas cylinder to be swingingly mounted thereon, the chord of the socket being in a plane at right angles to the axis of the barrel, and a straight vent connecting the bore of the barrel to the interior of the socket, said vent being so disposed as to permit a straight cleaning tool to be inserted through the vent from without the socket.

8. In a gas-operated firearm, a barrel, an arcuate socket carried by the barrel of the firearm and arranged to receive the mating end of a gas cylinder to be swingingly mounted thereon, the chord of the socket being in a plane at right angles to the axis of the barrel, and a straight vent connecting the bore of the barrel to the interior of the socket, said vent being inclined outwardly and rearwardly to permit a straight cleaning tool to be inserted through the vent from without the socket.

9. In a gas-operated rearm, a barrel, an arcuate socket carried by the barrel of the rearm and arranged to receive the mating end of a gas cylinder to be swingingly mounted thereon, the chord of the socket being in a plane at right angles to the axis of the barrel, and 'a straight vent connecting the bore of the barrel to the interior of the socket, said vent being inclined out- Wardly and rearwardly, and communicating with the socket at the pole of the same to permit a straight cleaning tool to be inserted through the vent from without the socket.

10. In a gas-operated firearm, the combination of a barrel, an arcuate socket carried by the bar- `the breech mechanism of a firearm, the front end of the cylinder being open and being provided With a perimetrally disposed arcuate surface arranged to engage and swing in the socket, the merging of the arcuate exterior surface of the cylinder wall and the annular edge of the cylinder bore providing a cutting profile which, when the cylinder is swung relative to the socket, removes accumulation of carbon and other foreign deposits from the wall of the socket.

RUSSELL J. TURNER. 

